Research and development of the present invention and application have not been federally sponsored, and no rights are given under any Federal program.
Not applicable
1. Field of the Invention
This invention relates to a means for securing the waterproof caps or boots of ignition wires to spark plugs, the distributor cap and/or coil on internal combustion engines.
2. Description of the Related Art Including Information Disclosed Under 37 CFR xc2xa7xc2xa71.97-1.98
The boot or cap of the present invention is suitable for securing distributor wires and spark plug connections on internal combustion engines. The purpose is to provide a cap or boot wire connection which fits securely and tightly around the wiring and spark plug connector in order to prevent moisture from creeping into electric connection and especially to prevent the wire from vibrating off the plug during travel over rough roads and at high speeds typically encountered in the racing car environment. The present invention is particularly useful in racing cars, because the vibration and heat etc. involved in the high performance runs of such vehicles often cause a spark plug wire to either come completely off the ends of the spark plug and cause missing and loss of power in the engine or to become partially loose and cause a breakdown in the conductivity and degradation of the spark and consequent loss of power and an increase in vehicle emissions. Another area in which the improvement is of great value is marine engine applications.
Various remedies have been sought for this condition and said remedies generally include elaborate connecting means involving snaps and nuts bolted to secure the wire. Such designs are time consuming to connect and disconnect as well as adding measurable weight to a car which is particularly critical in racing environments.
Where time is at an extreme premium during pits stops in a race, it is essential that any service such as the necessary changing of spark plugs during the pit stop be effectuated in the minimum amount of time. Therefore, any complicated mechanical additions to the spark plug and/or wiring are unsuitable. It is essential, however, that the proper spark be assured continuously and this requires limiting the number of disconnects in the wiring harness.
The closest prior art references of which the applicant is aware are set forth in the following paragraphs.
At the present there is no suitable device available to accomplish applicant""s objectives. The closest prior art reference from a general structural point of view is U.S. Pat. No. 3,193,615 to Burrows, disclosing a waterproof cap with an integral O-ring that serves primarily as a moisture seal, as opposed to a securing ring to prevent the cap from slipping off the end of the plug.
U.S. Pat. No. 5,344,328 to Suggs discloses a spark plug keeper which essentially has a ring shaped base which fits under the lower portion of the spark plug hex nut and bears against the underside of the hex nut to support a binding strap which straps around the upper end of the plug on the exterior of the boot. The interior of the boot is provided with internal flexible barbs to assist in holding the boot and maintaining it in electrical engagement with the spark plug.
Another relevant patent is Australian 145,131, which requires a special type of spark plug with a machined groove to accept a flange on the boot. The Australian boot seals the entire spark plug which permits the transfer of heat directly to the boot leading to premature failure.
U.S. Pat. No. 1,245,931 to Lanman shows a spark plug protector or boot, which is provided with screw adjustable rings on the plug-end lead as well as the wire-end lead that are screwed tightly to help secure the plug.
References that are of background interest only are:
U.S. Pat. No. 5,127,840 to Bezusko, et al: SPARK PLUG CONNECTOR
U.S. Pat. No. 5,188,537 to Itoh: FOR A SLIPPAGE PREVENTOR AND IGNITION TERMINAL CABLE
U.S. Pat. No. 1,928,520 to Werner: FOR SHROUDING CAP FOR SPARK PLUGS
None of these references show a simple, effective way for assuring the secure attachment of the spark plug shroud or wire cap to the spark plug electrode as contrasted with applicant""s design. The device of this invention, which may be readily utilized, is simple in structure, and low in cost. Furthermore, this unique design can be used on modern type engines where the spark plug is recessed into or below the surface of the cylinder head. The new recessed engine designs are responsible for much of the increased fuel mileage and improved performance of today""s vehicles. The cited references cannot be used with these modern head configurations since they physically will not fit or there is no room to manipulate their securing procedure.
The present invention provides positive control to prevent the wire boot cap from coming off the end of the plug because the tapered sleeve with concentric recesses cooperates with the internally ringed boot cap to secure the structure to that of the hub of the spark plug or distributor terminal.
This present invention provides an improved rubber insulator cover and cooperating sleeve for spark plug lead wires including a means of connecting the cap and the wire securely to the end of the spark plug in such a manner as to prevent the unwanted disconnection of the wire lead from the spark plug outer electrode.
This is achieved by providing a plurality of internal annular grooves in the portion of the rubber cap which fits over the end of the spark plug and engages the cooperating internal grooves of a hard plastic or rubber sleeve which fits over the spark plug terminal and holds the cap material tightly thereon making it impossible for the cap to slip off inadvertently due to heat, vibration and the like.
The device of this invention is designed for use on conventional spark plugs consisting of the spark electrode, threaded base, insulated porcelain cover parts and the threaded electrode contact at the end of which the distributor wire is usually fitted to the connection in a simple friction or spring fitted connection and consequently, it is subject to loosening and disconnection due to engine and road vibration.
The boot covers the electrode lead wire and at a point corresponding to where it fits over the head of the plug has specially formed, generally concentric grooves in the boot designed to engage mating projections in a tapered sleeve which fits over the spark plug terminal making it physically impossible for the wire to become disconnected from the plug electrode. The sleeve is extremely inexpensive yet effective.
An alternate embodiment of the invention comprises a boot including molded internal grooves and steel spring clips molded within the grooves to exert a clamping force on the spark plug sleeve. The boot can also include molded internal grooves combined with an outer recess to receive with an external wire tie.
Accordingly, an object of this invention is to provide a new and improved terminal cap for connecting the ignition wire to a spark plug or distributor cap in internal combustion engines.
Another object of this invention is to provide a new and improved and inexpensive terminal cap that securely fastens to a spark plug or distributor cap.
A further object of this invention is to provide a new and improved internally grooved boot, which engages the external grooves on a sleeve mounted over a spark plug terminal.
A more specific object of this invention is to provide a new and improved terminal cap for spark plugs which includes a plurality of internally molded grooves which engages a spark plug sleeve with internally molded mating grooves to hold the spark plug in a firm connection.